The present invention relates to the starting of aircraft engines and to the driving of auxiliary on-board equipment.
The German printed patent application No. 1,928,235 describes a device for starting an aircraft engine by means of a hydrodynamic torque converter permitting particularly the driving of auxiliary equipment which, in turn, can be tested and if found operational, the engine is started while driving of the auxiliary equipment continues. This device, however, poses some problems because the control of the torque converter is quite cumbersome having to do with the volumetric efficiency.
The U.S. Pat. No. 3,416,309 discloses a starter motor which is driven by the hot exhaust gases developed by a gas generator, and the starter motor starts the engine via a gear box. This system is not suitable for testing the function of auxiliary equipment prior to starting the engine and to obtain a changeover to the engine as equipment drive without interrupting operation of the equipment.
The U.S. Pat. No. 3,660,977 discloses an on-board emergency power source, wherein particularly a monocomponent fuel is used to develop propulsion gas for driving a turbine which, in turn, drives an hydraulic pump via a suitable gear. This particular patent is not concerned with starting of an engine but relates exclusively to the production of hydraulic power in the case of equipment failure leading to the drop out of the regular hydraulic power source.
U.S. Pat. No. 2,777,301 discloses an air conditioning system integrated in a device for starting an aircraft engine using air tapped from the compressor of an auxiliary gas turbine. The particular device is exclusively designated for producing mechanical motor power to the engine for starting it.